The invention relates to photon detectors, particularly to an ultraviolet detector which involves the conversion of ultra-violet photons into electrons and subsequent amplification of these electrons via generation of electron avalanches.
Photon detectors operate by converting photons into electronic signals that can be processed into pulses or images. These include devices such as photodiodes, photomultiplier tubes, vidicons, charged-coupled devices (CCD's) etc. All photon detectors are characterized by their sensitivity to photons as a function of photon energy, their ability to amplify incident photons into large electrical signals proportional to the incident photon intensity (gain), their ability to distinguish fine detail in an image (position resolution), their temporal response to incident photons (time resolution), and their inherent noise level (dark current).
Various types of photon detectors and detection systems have been developed for various applications. These prior detectors and detection/imaging systems are exemplified by the following U.S. Pat. No. 5,032,729 issued Jul. 16, 1991 to G. Charpak; U.S. Pat. No. 5,001,348 issued Mar. 19, 1991 to R. Dirscherl et al.; U.S. Pat. No. 4,889,994 issued Dec. 26, 1989 to A. R. Brown et al.; U.S. Pat. No. 4,871,915 issued Oct. 3, 1989 to K. C. Prince; U.S. Pat. No. 4,614,871 issued Sep. 30, 1986 to J. N. Driscoll; U.S. Pat. No. 3,965,354 issued Jun. 22, 1976 to J. C. Fletcher et al.; U.S. Pat. No. 3,952,197 issued Apr. 20, 1976 to J. A. R. Samson; U.S. Pat. No. 3,656,019 issued Apr. 11, 1972 to R. W. Storve and U.S. Pat. No. 3,342,995 issued Sep. 19, 1967 to R. E. Axmark.
Imaging in high radiation environments, such as in nuclear reactors, normal ultra-violet (UV) sensitive CCD cameras and vidicon TV cameras are plagued by noise pickup. Also, the prior known systems are not greatly effective when used in extremely low light level sensitivity television cameras. While photomultiplier tubes are widely utilized in the field of ultra-violet radiation detection they are expensive and susceptible to magnetic field.
The Superconducting Super Collider, when developed will require scintillation counters, and sets forth a need to instrument roughly 6000 square meters of liquid or solid scintillator with photodetectors that are rugged, radiation-hardened, and able to operate in a high magnetic field. This need is not easily fulfilled from a operation and cost effective standpoint by the prior known photomultiplier tubes due to their cost and susceptibility to magnetic fields. Thus, there is a need for a simple yet effective ultra-violet sensitive detector.
The above need is satisfied by the microgap ultra-violet detector of this invention which is of simple construction, exhibits photon sensitivity over a wide range of energies, exhibits fast time response, provides adjustable gain, and exhibits low noise. Unlike CCD detectors, the present invention is not subject to radiation damage.